doc: add links between cork() and uncork()
Writable.cork() and Writable.uncork() are meant to be documented together, but we maintain a lexicographic order. This commit introduces some links between the two.
Fixes: https://github.com/nodejs/node/issues/7340
Implements @addaleax suggestion in https://github.com/nodejs/node/issues/7340#issuecomment-227321283
Checklist
-
documentation is changed or added -
commit message follows commit guidelines
Affected core subsystem(s)
doc, stream